Adjusted stiffness orthopaedic implants and method of manufacture

ABSTRACT

An orthopaedic implant includes: a first porous ingrowth material region; a second porous ingrowth material region coupled to the first porous ingrowth material region; and an intermediate region disposed between the first porous ingrowth material region and the second porous ingrowth material region. The intermediate region has a stiffness that differs from at least one of the first porous ingrowth material region or the second porous ingrowth material region.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a non-provisional application based upon U.S. Provisional PatentApplication Ser. No. 62/775,498, entitled “ ADJUSTED STIFFNESSORTHOPAEDIC IMPLANTS AND METHOD OF MANUFACTURE”, filed Dec. 5, 2018,which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to medical implants and, moreparticularly, to orthopaedic implants.

2. Description of the Related Art

Orthopaedic implants are commonly used to replace and/or repairanatomical structures of a patient that have been damaged due to diseaseand/or injury. To be successful, the implant needs to have sufficientstrength. If the strength of the implant is not sufficient, the implantcan fail and require a revision. While known implants can be successful,implant failure rates and the rate of adverse patient events remainhigher than desired.

What is needed in the art is an implant that can address some of thepreviously described issues of known implants.

SUMMARY OF THE INVENTION

Exemplary embodiments disclosed herein provide orthopaedic implants withan implant stiffness that can be adjusted based on patient requirements.

In some exemplary embodiments provided according to the presentdisclosure, an orthopaedic implant includes: a first porous ingrowthmaterial region; a second porous ingrowth material region coupled to thefirst porous ingrowth material region; and an intermediate regiondisposed between the first porous ingrowth material region and thesecond porous ingrowth material region. The intermediate region has astiffness that differs from at least one of the first porous ingrowthmaterial region or the second porous ingrowth material region.

In some exemplary embodiments provided according to the presentdisclosure, an orthopaedic implant includes: a porous ingrowth materialbody having at least one opening and at least one stiffness adjustingfeature; and at least one reinforcing element placed in the at least onestiffness adjusting feature and configured to reinforce the porousingrowth material body in at least one direction.

In some exemplary embodiments disclosed herein, a method ofmanufacturing multiple orthopaedic implants is provided. The methodincludes: producing a strip of material comprising a composite of afirst porous ingrowth material and a second porous ingrowth material;forming a plurality of through-openings in the strip; and cutting aplurality of implant blanks from the strip, each of the implant blankscomprising at least one of the formed through-openings.

One possible advantage that may be realized by exemplary embodimentsdisclosed herein is that the stiffness of the orthopaedic implant may beadjusted to match the specific requirements of a patient to reduce therisk of providing an overly stiff implant.

Another possible advantage that may be realized by exemplary embodimentsdisclosed herein is that the orthopaedic implants may be produced in aneconomical manner.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a side view of an exemplary embodiment of an orthopaedicimplant including an intermediate region, provided according to thepresent disclosure;

FIG. 2 is an exploded view of the orthopaedic implant of FIG. 1;

FIG. 3 is a side view of an exemplary embodiment of an orthopaedicimplant including a tapered intermediate region, provided according tothe present disclosure;

FIG. 4 is a side view of an exemplary embodiment of an orthopaedicimplant including an intermediate region with a stiffness adjustingfeature, provided according to the present disclosure;

FIG. 5 is a top view of the orthopaedic implant of FIG. 4;

FIG. 6A is a perspective view of an exemplary embodiment of anorthopaedic implant including a plurality of reinforcement elements,provided according to the present disclosure;

FIG. 6B is a partial cut-away view of the orthopaedic implant of FIG.6A;

FIG. 7 is a perspective view of an exemplary embodiment of anorthopaedic implant including an intermediate region with a pair ofstiffness adjusting features, provided according to the presentdisclosure;

FIG. 8 is a perspective view of an exemplary embodiment of anorthopaedic implant including a cutout that has a reinforcing materialdisposed therein, provided according to the present disclosure;

FIG. 9 is a perspective view of an exemplary embodiment of anorthopaedic implant including an intermediate region and a plurality ofreinforcing ribs, provided according to the present disclosure;

FIG. 10 is a perspective view of an exemplary embodiment of anorthopaedic implant including an intermediate region that is partiallywrapped with a wrapping porous ingrowth material and a plurality ofreinforcing ribs, provided according to the present disclosure;

FIG. 11 is a perspective view of an exemplary embodiment of anorthopaedic implant including an intermediate region and a plurality ofreinforcing ribs having rib cutouts, provided according to the presentdisclosure;

FIG. 12 is a perspective view of an exemplary embodiment of anorthopaedic implant including an intermediate region that is wrappedwith a wrapping porous ingrowth material and a plurality of reinforcingribs, provided according to the present disclosure;

FIG. 13 is a perspective view of an exemplary embodiment of a strip ofmaterial that may be used to form a plurality of orthopaedic implants,provided according to the present disclosure;

FIG. 14 is a front view of the strip of material of FIG. 13;

FIG. 15 is a top view of the strip of material of FIGS. 13-14 with aplurality of through-openings formed therein and illustrated cleavelines; and

FIG. 16 is a perspective view of another exemplary embodiment of a stripof material may be used to form a plurality of orthopaedic implants,provided according to the present disclosure.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate embodiments of the invention and such exemplifications arenot to be construed as limiting the scope of the invention in anymanner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIGS. 1-2, anexemplary embodiment of an orthopaedic implant 100 is illustrated. Theorthopaedic implant 100 has the general shape of a spinal implant, suchas a vertebral implant, for implantation within the spine of a human ora non-human animal. As illustrated, the implant 100 includes a firstporous ingrowth material region 110, a second porous ingrowth materialregion 120, and a separate porous or nonporous intermediate region 130disposed between the ingrowth material regions 110, 120. As used herein,an “intermediate region” may also be referred to as a “stiffnessmodulating region” and/or a “stiffness adjusting region.” Theintermediate region 130 has a top surface 132 connected to a bottomsurface 111 of the material region 110 and a bottom surface 131connected to a top surface 122 of the material region 120. Asillustrated, the top surface 132 and the bottom surface 131 of theintermediate region 130 are both substantially flat, i.e., planar, sothe orthopaedic implant 100 is a “flat” spinal implant. The bottomsurface 111 of the material region 110 and the top surface 122 of thematerial region 120 are similarly flat. A top surface 112 of thematerial region 110 and a bottom surface 121 of the material region 120,on the other hand, may be angled to conform to the natural anatomicalshape of vertebrae that will bear on the respective surfaces 112, 121.The material regions 110 and 120 may also have respective peripheralsurfaces, such as surfaces 113 and 123, that are substantially planarwith one another and a peripheral surface 133 of the intermediate region130. In some embodiments, a through-hole (not seen) may be formedthrough the implant 100 that extends from the top surface 112 of thematerial region 110 through the intermediate region 130 and to thebottom surface 121 of the material region 120. It should be appreciatedthat while the implant 100 is illustrated and described as having threedistinct regions 110, 120, 130, in some embodiments the implant 100 hasfewer than three regions, i.e., one or two regions, or more than threeregions, e.g., four, five, or more than five regions. Further, while theimplant 100 is illustrated and described as a spinal implant, theimplant may be formed as a different type of orthopaedic implant, suchas a knee implant, in accordance with the present disclosure.

The material regions 110 and 120 may comprise a similar, or the same,biocompatible material that is porous to encourage tissue ingrowth andfixation of the implant 100. Exemplary materials that may be used toform the material regions 110 and 120 include, but are not limited to:metals such as titanium, stainless steel, cobalt chrome, and/ortantalum; polymers such as ultra-high molecular weight polyethylene(UHMWPE), other forms of polyethylene, polyaryl ether ketone (PAEK) suchas polyether ether ketone (PEEK), polycarbonate urethane (PCU),polylactic acid (PLA),and/or polyglycolic acid (PGA); and/or ceramicssuch as hydroxyapatite (HA), high-density alumina, so-called “Bioglass,”and graphite. The porosity of the material regions 110, 120 may bevaried to alter tissue ingrowth characteristics into the materialregions 110, 120. The porosity of the material regions 110, 120 may be,for example, between 30% and 70% to encourage tissue ingrowth into thematerial regions 110, 120. An exemplary material that may be used toform the material regions 110, 120 is commercially available under thetradename OSTEOSYNC® from SITES MEDICAL® of Columbia City, Ind.

The intermediate region 130 may also comprise a porous biocompatiblematerial, similar to the material regions 110, 120, that has a differentstiffness, which may be either higher or lower, than the materialregions 110, 120. In this sense, the intermediate region 130 may act asa stiffness modulating core to provide the implant 100 with the desiredstiffness, which will typically be different than the stiffness inmaterial regions 110, 120. As used herein, the “stiffness” of thematerial corresponds to the Young's modulus (E) of the material(s) ofthe regions 110, 120, 130. In some embodiments, the intermediate region130 comprises a relatively high stiffness material, compared to thematerial regions 110, 120, such as titanium, cobalt chrome, PEEK, orpolycarbonate urethane. The stiffness of the intermediate region 130 maybe higher than the material regions 110, 120 due to, for example, theintermediate region 130 having a different material composition with agenerally stiffer material than the material regions 110, 120, changingthe shape of the intermediate region 130 compared to the materialregions 110, 120, and/or by forming the material regions 110, 120 and/orthe intermediate region 130 with stiffness adjusting features, as willbe described further herein. In some embodiments, the intermediateregion 130 comprises the same material composition as the materialregions 110, 120 but is formed with a lower porosity so the intermediateregion 130 has a greater stiffness than the material regions 110, 120.In some embodiments, the intermediate region 130 comprises a relativelylow stiffness material, compared to the material regions 110, 120, tolower the overall stiffness of the implant 100. It should be appreciatedthat the intermediate region 130 may also comprise one or more regionsof a relatively high stiffness material as well as one or more regionsof a relatively low stiffness material to provide the desired stiffnesscharacteristics.

Referring now to FIG. 3, another exemplary embodiment of an orthopaedicimplant 300 is illustrated that is similar to the orthopaedic implant100 but is formed with a porous intermediate region 330 with a taperedbottom surface 331 and a tapered top surface 332 to define a lordoticangle La. The intermediate region 330 is disposed between a first porousingrowth material region 310 and a second porous ingrowth materialregion 320. The material region 310 may have a flat bottom surface 311connected to the tapered top surface 332 of the intermediate region 330and the material region 320 may have a flat top surface 322 connected tothe tapered bottom surface 331 of the intermediate region 330. In thissense, the lordotic angle La defined by the tapered surfaces 331, 332 ofthe intermediate region 330 defines the lordotic angle of the implant300. The intermediate region 330 may be formed to define a lordoticangle La ranging between, for example, 3° and 15°, depending on thepatient anatomy at the implantation site. Other than the implant 300being provided with the lordotic angle La, the implant 300 may be formedsimilarly to the implant 100 illustrated in FIGS. 1-2 and include theintermediate region 330 to modulate the implant stiffness, so furtherdescription is omitted for the sake of brevity.

Referring now to FIGS. 4-5, another exemplary embodiment of an implant400 formed according to the present disclosure is illustrated. Theimplant 400 may be formed as a flat spinal implant, similarly to thepreviously described implant, with a first porous ingrowth materialregion 410, a second porous ingrowth material region 420, and a porousintermediate region 430 disposed between the material regions 410 and420. While illustrated as being formed as a flat implant, in someembodiments the implant 400 is provided with a lordotic angle.

The implant 400 may have a through-hole 501 (illustrated in FIG. 5) thatextends from top to bottom through the ingrowth material regions 410,420 and the intermediate region 430 as well as one or more additionalopenings 434 formed through a peripheral surface 433 of the intermediateregion 430 to adjust the stiffness of the intermediate region 430, andthus the overall stiffness of the implant 400. In some embodiments, theadditional opening 434, which may also be referred to as a “stiffnessadjusting feature,” extends through the intermediate region 430 from oneside, such as side 435A, to an opposite side 435B of the intermediateregion 430. In this respect, the stiffness adjusting feature 434 is avoid formed in the intermediate region 430 that reduces the overallstiffness of the implant 400, the significance of which will bedescribed further herein. The stiffness adjusting feature 434 defines avolume of material removed from the intermediate region 430 that may beadjusted to provide the implant 400 with a desired stiffness. The volumeof material removed from the intermediate region 430 to obtain thedesired stiffness may depend, for example, on the material compositionof the intermediate region 430 as well as desired stiffnesscharacteristics. It should thus be appreciated that while the stiffnessadjusting feature 434 is illustrated as an opening of constantrectangular cross-section formed through the intermediate region 430,the stiffness adjusting feature 434 may have other cross-sectionalshapes, which may vary through the intermediate region 430. Further, itshould be appreciated that while the stiffness adjusting feature 434 isillustrated as being formed in the intermediate region 430, one or morestiffness adjusting features may also be formed in the material regions410, 420. In other respects, the implant 400 may be similar to thepreviously described implants 100 and 300.

Referring now to FIGS. 6A and 6B, another exemplary embodiment of anorthopaedic implant 600 formed according to the present disclosure isillustrated. Unlike the previously described implants 100, 300, 400, theorthopaedic implant 600 may have a shape that is substantially formedwith a single porous ingrowth material body 610, i.e., the implant 600does not have a distinct porous intermediate region between two porousingrowth material regions. The material body 610 may comprise similarmaterials to the previously described ingrowth material regions, such asingrowth material region 110. As illustrated, the material body 610 mayhave a through-hole 611 extending through the material body 610 from atop surface 612 to a bottom surface 613, which may be a feature for bonegraft placement and/or a stiffness adjusting feature that can change theoverall stiffness of the material body 610. The material body 610 mayalso have one or more peripheral surfaces, such as peripheral surface614, that is formed with one or more additional stiffness adjustingfeatures, such as openings 615A, 615B, that extend through theperipheral surface 614. In some embodiments, the openings 615A, 615B areof similar size and shape and both extend to the through-hole 611. Theperipheral surface 614 may also have a threaded opening 616 formedtherein to, for example, couple with an instrument for placement of theimplant 600 at an implantation site.

In some embodiments, the implant 600 further includes one or morereinforcing elements, shown as pins 620A, 620B, 620C, to increase thestrength of the implant 600 in certain directions. As illustrated inFIG. 6B, for example, the pins 620A, 620B, 620C may be placed incorresponding pin openings 621A, 621B, 621C that extend from the topsurface 612 toward the bottom surface 613 of the material body 610. Thepins 620A, 620B, 620C may comprise, for example, titanium, PEEK, oranother type of relatively high strength material. As can beappreciated, the material body 610 has a void (through-hole 611) formedtherein with a significant volume. While the void 611 provides thematerial body 610 with desired bone graft placement and stiffnesscharacteristics in, for example, medial-lateral and anterior-posteriordirections, the torsional, shear, or compressive strength of thematerial body 610 may be insufficient without reinforcement. Thus, thepins 620A, 620B, 620C may be provided to reinforce the material body 610in a direction of compression so the implant 600 has sufficientcompressive strength to withstand normal loading without a significantrisk of failure.

Referring now to FIG. 7, another exemplary embodiment of an orthopaedicimplant 700 formed according to the present disclosure is illustrated.The orthopaedic implant 700 has a similar shape to the implant 600illustrated in FIGS. 6A-6B, but has a pair of porous ingrowth materialregions 710, 720 with a porous or nonporous intermediate region 730disposed between the material regions 710, 720, similarly to thepreviously described implants 100, 300, and 400. The material regions710, 720 may comprise materials similar to, for example, previouslydescribed material regions 110, 120 and the intermediate region 730 maycomprise materials similar to, for example, previously describedintermediate region 130. In some embodiments, the material of theintermediate region 730 has a different stiffness than the material ofthe material regions 710 and 720.

The implant 700 may have a through-hole 701 extending from a top surface712 of the material region 710 to a bottom surface 721 of the materialregion 720 through the intermediate region 730. The intermediate region730 may also have a pair of stiffness adjusting features, illustrated asopenings 731A, 731B, formed in a peripheral surface 732 and anadditional stiffness adjusting feature, illustrated as another opening733, formed in another peripheral surface 734. The openings 731A, 731Bmay have a same or similar size and shape relative to one another, butdiffer in size and shape from the opening 733. In this respect, theopenings 731A, 731B, 733 formed in the intermediate region 730 can havedifferent effects on the stiffness of the intermediate region 730, andthus the stiffness of the implant 700. In some embodiments, theperipheral surface 732 also has a threaded opening 735 formed thereinto, for example, couple with an insertion tool for inserting the implant700.

Referring now to FIG. 8, another exemplary embodiment of an orthopaedicimplant 800 formed according to the present disclosure is illustrated.The orthopaedic implant 800 may be formed with a single porous ingrowthmaterial body 810, similarly to the previously described implant 600.The material body 810 may be formed with one or more peripheral surfaces811 having a cutout 812 formed therein. A reinforcing material 820,which comprises a material with a higher strength than the material ofthe material body 810, may be placed in the cutout 812 to reinforce theimplant 800 and increase the strength of the implant 800. In thisrespect, the reinforcing material 820 contacts boundary surfaces of thecutout 812 and acts similarly to a window frame to increase the strengthof the material surrounding the cutout 812 rather than including, forexample, reinforcing pins. In other respects, the implant 800 can besimilar to the implant 600, so further description is omitted forbrevity.

Referring now to FIGS. 9-12, additional exemplary embodiments oforthopaedic implants 900, 1000, 1100, 1200 formed according to thepresent disclosure are illustrated. As can be seen, each of the implants900, 1000, 1100, 1200 includes a respective first porous ingrowthmaterial region 910, 1010, 1110, 1210, a respective second porousingrowth material region 920, 1020, 1120, 1220, and a respective porousor nonporous intermediate region 930, 1030, 1130, 1230 disposed betweenthe material regions 910, 920, 1010, 1020, 1110, 1120, 1210, 1220. Thematerial regions 910, 920, 1010, 1020, 1110, 1120, 1210, 1220 maycomprise the same materials as, for example, the previously describedmaterial regions 110 and 120 and the intermediate regions 930, 1030,1130, 1230 may comprise the same materials as, for example, thepreviously described intermediate region 130. As illustrated, theimplants 900, 1000, 1100, 1200 can be formed to have a substantiallydomed shape. Each of the implants 900, 1000, 1100, 1200 can be formedwith a through-opening 901, 1001, 1101, 1201 that extends from a topsurface 902, 1002, 1102, 1202 to a bottom surface 903, 1003, 1103, 1203of the implant 900, 1000, 1100, 1200. One or more reinforcing ribs 904A,904B, 1004A, 1004B, 1104A, 1104B, 1204A, 1204B may be disposed in thevoid formed by the through-opening 901, 1001, 1101, 1201, rather thanleaving the void empty. In some embodiments, the ribs 904A, 904B, 1004A,1004B, 1104A, 1104B, 1204A, 1204B are formed as a result of forming thethrough-opening 901, 1001, 1101, 1201. Additionally, one or morestiffness adjusting features, such as openings 931A, 931B, 931C, 931D,1031A, 1031B, 1031C, 1031D, 1131A, 1131B, 1231A, 1231B, 1231C, 1231D,may be formed in the intermediate region 930, 1030, 1130, 1230 andextend to the through-opening 901, 1001, 1101, 1201. Threaded openings932A, 932B, 1032A, 1032B, 1132, 1232A, 1232B may also be formed in theintermediate region 930, 1030, 1130, 1230 to interact with an insertiontool for inserting the implant 900, 1000, 1100, 1200 at an implant site.

Referring specifically now to FIG. 9, it may be seen that the implant900 has reinforcing ribs 904A, 904B that may be formed of the samematerial as the intermediate region 930 to modify the stiffness of theimplant 900 compared to, for example, if the void formed by thethrough-opening 901 was left empty. The ribs 904A, 904B may be partiallycovered by the material region 910 on top and the material region 920 onbottom. As illustrated, the ribs 904A, 904B may be solid, i.e., formedwithout voids therein.

Referring specifically now to FIG. 10, it may be seen that theintermediate region 1030 is “wrapped” with a porous ingrowth materialregion 1040 that may comprise a material similar to the material(s) ofthe material regions 1010, 1020. As illustrated, the wrapping materialregion 1040 may wrap around some or all of an outer diameter 1033 of theintermediate region 1030 to provide a more porous material on theintermediate region 1030 for tissue ingrowth. In other respects, theimplant 1000 may be similar to the implant 900.

Referring specifically now to FIG. 11, it may be seen that the implant1100 has reinforcing ribs 1104A, 1104B that are formed with rib cutouts1105A, 1105B to decrease the stiffness of the respective ribs 1104A,1104B. In all other respects, the implant 1100 may be similar to theimplant 900.

Referring specifically now to FIG. 12, it may be seen that theintermediate region 1230 is “wrapped” with a porous ingrowth materialregion 1240 on some or all of an outer diameter 1233 of the intermediateregion 1230, similarly to the intermediate region 1030 of the implant1000. The implant 1200 further includes another porous ingrowth materialregion 1250 that is “wrapped” around some or all of an inner diameter1234 of the intermediate region 1230, so both the outer diameter 1233and the inner diameter 1234 of the intermediate region 1230 are at leastpartially wrapped in porous ingrowth material. In other respects, theimplant 1200 may be similar to the implant 1000.

It has been found that, in many instances, the stiffness of anorthopaedic implant does not need to be as high as possible to promotehealing of the patient. Rather, in certain instances the implant may beformed with too high of a stiffness to the detriment of the patient. Forexample, in spinal implants, the implant having an overly high stiffnesscan lead to vertebral endplates of the spine fracturing followingimplantation, even under loads that would not normally fracture theendplates. This type of fracturing is due to the overly high stiffnessof the implant transmitting excessive loads to surrounding anatomicalstructures, rather than deforming to absorb some of the load. Theexcessive transmitted loads lead to instances where the surrounding boneis subjected to higher-than-normal stress, causing fracturing, whensubjected to loads that normally would not cause fracturing.

On the other hand, the stiffness of the implant must be sufficientlyhigh to support the surrounding anatomical structures. If the stiffnessof the implant is too low, the implant does not provide the propersupport for the spinal column, which can lead to abnormal curvature ofthe spine and significantly increase the risk of spinal injuries. Thus,the stiffness of the implant is of particular concern when designing theimplant because too high or too low of a stiffness tends to increase therisk of adverse effects following implantation.

In the context of this finding, the implants 100, 300, 400, 600, 700,800, 900, 1000, 1100, and 1200 formed according to the presentdisclosure may have a stiffness that falls within a range that is nottoo high, which could lead to abnormal bone fracturing, but also not solow that the surrounding anatomical structures are not adequatelysupported. The stiffness of the implants 100, 300, 400, 600, 700, 800,900, 1000, 1100, and 1200 may be adjusted as previously described toprovide the desired stiffness. Thus, the implants 100, 300, 400, 600,700, 800, 900, 1000, 1100, and 1200 formed according to the presentdisclosure can adequately support the surrounding anatomical structureswithout an abnormal risk of fracturing surrounding bone followingimplantation.

In some exemplary embodiments, a method of forming an orthopaedicimplant with a patient-adjusted stiffness is provided. As used herein, a“patient-adjusted” stiffness may refer to a stiffness of an implant thatis provided for a specific patient, i.e., a single patient, or aspecific patient population, i.e., a population of patients that sharecommon medically significant characteristics, such as havingosteoporosis, scoliosis, and/or arthritis. To form the implant, such asthe orthopaedic implant 100, an amount of stiffness that the implantrequires to treat a patient is determined. Determining the stiffness mayinclude, for example, evaluating a condition of the patient anatomy anda medical history of the patient. The determining may includevisualizing the patient anatomy at an implantation site using, forexample, magnetic resonance imaging (MRI) or x-ray imaging techniques todetermine the progression of disease in the patient as well as the shapeof anatomical features surrounding the implantation site. In someembodiments, determining the stiffness may include comparing thecondition of the patient anatomy to comparable patient anatomies andderiving the stiffness from the comparison. It should thus beappreciated that many different techniques may be used to determine thestiffness required to treat the patient. In some embodiments, therequired stiffness may be similar to the stiffness of the nativeanatomical structures of the patient, e.g., vertebrae of the patient, sothe produced implant has a “modulus match” with the anatomy of thepatient.

Once the required stiffness is determined, the implant may be formedsuch that the formed implant has the required stiffness. In someembodiments, forming the implant includes providing an implant having ashape and modifying the implant to have the required stiffness.Modifying the implant may include, for example, forming one or morestiffness adjusting features in the implant, as previously described.Modifying the implant may also include adjusting a material forming oneor more regions of the implant, such as porous ingrowth material regionsor an intermediate region, by, for example, changing the porosity,changing the shape, or changing the composition of the adjustedmaterial. After the implant is formed with the required stiffness, theimplant may be delivered to a healthcare provider, such as a surgeon,and implanted within a patient at an implantation site.

From the foregoing, it should be appreciated that the present disclosureprovides methods for producing implants with an appropriate stiffnessfor the desired application. The method allows production of implantsthat are not so stiff that abnormal bone fracturing becomes asignificant issue while also providing sufficient support for thesurrounding anatomical structures. Thus, implants can be produced withan appropriate stiffness to heal the patient without significantlyincreasing the risk of detrimental effects, such as abnormal bonefracturing, following implantation.

In some embodiments, a method of manufacturing multiple orthopaedicimplants, such as the implant 300 illustrated in FIG. 3, is provided.Each of the produced implants may have similar stiffness and shapes, aswill be appreciated from the further description provided herein.Referring specifically now to FIGS. 13-15, it can be seen that themethod may include producing a strip 1301 of material that will be usedto form the implant 300. The strip 1301 of material may be, for example,a composite of a first porous ingrowth material 1310, a second porousingrowth material 1320, and a porous intermediate material 1330 disposedbetween the ingrowth materials 1310, 1320. The intermediate material1330 may be formed with a top surface and a bottom surface that definesthe lordotic angle La of the implant 300, as previously described. Insome embodiments, a plurality of holding openings 1302, 1303 are formedon opposite ends 1304, 1305 of the strip 1301 for holding the strip 1301with, for example, clamps.

Referring specifically now to FIG. 15, it can be seen that a pluralityof through-openings 1501 have been formed in the strip 1301. Each of thethrough-openings 1501 corresponds to an implant that will be formed fromthe strip 1301, i.e., nine through-openings 1501 are formed in the strip1301, corresponding to nine implants being formed from the strip 1301.The through-openings 1501 may be formed in the strip 1301 in anysuitable fashion such as, for example, punching, machining, etc. In someembodiments, the materials 1310, 1320, 1330 forming the strip 1301 haveopenings formed therein prior to bonding to produce the through-openings1501 through the strip 1301.

To form implants from the strip 1301, individual implants are cut fromthe strip 1301 into the shape of the final implant. As illustrated inFIG. 15, for example, the strip 1301 can be cut along cleave lines 1502to form a plurality of implant blanks 1503. After the implant blanks1503 are separated from one another, the implant blanks 1503 may bemachined, if necessary, to the final implant shape or packaged andsterilized before being shipped for implantation. In some embodiments,one or more of the implant blanks 1503 can also be processed to adjust astiffness the final implant, as previously described.

Referring now to FIG. 16, another exemplary embodiment of a strip 1601that may be used to make flat implants, i.e., implants without alordotic angle, is illustrated for producing, for example, the implant100 illustrated in FIGS. 1-2. The strip 1601 is formed to have a firstporous ingrowth material 1610, a second porous ingrowth material 1620,and a porous intermediate material 1630 disposed between the ingrowthmaterials 1610, 1620. The porous intermediate material 1630 is providedwith a flat top surface and a flat bottom surface so the producedimplants do not define a lordotic angle. In all other respects, thestrip 1601 may be used to produce several individual implants similarlyto the previously described strip 1301.

From the foregoing, it should be appreciated that the present disclosureprovides methods for manufacturing multiple implants from a singlematerial source, which may be a strip, a sheet, or a blank. The materialsource may be kept readily on hand by a manufacturer and, when needed,processed to produce implants with the desired shape and stiffness.Strips of material, for example, may be kept on hand by a manufacturerto produce implants, as needed, reducing the need for storing manydifferent materials. It should thus be appreciated that the previouslydescribed method may increase manufacturing speed and reducemanufacturing cost by providing an easily handled and processed materialthat can be rapidly processed to produce one or more implants.

While this invention has been described with respect to at least oneembodiment, the present invention can be further modified within thespirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains.

What is claimed is:
 1. An orthopaedic implant, comprising: a firstporous ingrowth material region; a second porous ingrowth materialregion coupled to the first porous ingrowth material region; and anintermediate region disposed between the first porous ingrowth materialregion and the second porous ingrowth material region, the intermediateregion having a stiffness that differs from at least one of the firstporous ingrowth material region or the second porous ingrowth materialregion.
 2. The orthopaedic implant of claim 1, wherein the intermediateregion comprises a porous material.
 3. The orthopaedic implant of claim1, wherein the stiffness of the intermediate region is greater than astiffness of the first porous ingrowth material region and a stiffnessof the second porous ingrowth material region.
 4. The orthopaedicimplant of claim 1, wherein the stiffness of the intermediate region isless than a stiffness of the first porous ingrowth material region and astiffness of the second porous ingrowth material region.
 5. Theorthopaedic implant of claim 1, further comprising at least onestiffness adjusting feature formed in at least one of the intermediateregion, the first porous ingrowth material region or the second porousingrowth material region.
 6. The orthopaedic implant of claim 5, whereinthe at least one stiffness adjusting feature is formed in theintermediate region.
 7. The orthopaedic implant of claim 5, wherein theat least one stiffness adjusting feature is an opening.
 8. Theorthopaedic implant of claim 6, wherein the opening extends from a topsurface of the first porous ingrowth material region through theintermediate region to a bottom surface of the second porous ingrowthmaterial region.
 9. The orthopaedic implant of claim 8, wherein a voidis formed by the opening and at least one reinforcing rib is disposed inthe void.
 10. The orthopaedic implant of claim 9, wherein the at leastone reinforcing rib has a rib cutout formed therein.
 11. The orthopaedicimplant of claim 1, wherein the intermediate region is wrapped by awrapping porous ingrowth material region on at least a portion of anouter diameter of the intermediate region.
 12. The orthopaedic implantof claim 1, wherein the intermediate region comprises a tapered topsurface connected to the first porous ingrowth material region and atapered bottom surface connected to the second porous ingrowth materialregion to define a lordotic angle.
 13. An orthopaedic implant,comprising: a porous ingrowth material body comprising at least oneopening and at least one stiffness adjusting feature; and at least onereinforcing element placed in the at least one opening and configured toreinforce the porous ingrowth material body in at least one direction.14. The orthopaedic implant of claim 13, wherein the at least onereinforcing element comprises a pin.
 15. The orthopaedic implant ofclaim 14, wherein the at least one opening extends from a top surface ofthe porous ingrowth material body to a bottom surface of the porousingrowth material body, the pin being configured to reinforce the porousingrowth material body in a direction of compression.
 16. Theorthopaedic implant of claim 14, wherein the at least one openingcomprises a plurality of openings extending from the top surface to thebottom surface and the at least one reinforcing element comprises a pinplaced in each of the openings.
 17. The orthopaedic implant according toclaim 13, wherein the at least one opening is a cutout and the at leastone reinforcing element comprises a reinforcing material placed in thecutout and contacting boundary surfaces of the cutout.
 18. A method ofmanufacturing multiple orthopaedic implants, the method comprising:producing a strip of material comprising a composite of a first porousingrowth material and a second porous ingrowth material; forming aplurality of through-openings in the strip; and cutting a plurality ofimplant blanks from the strip, each of the implant blanks comprising atleast one of the formed through-openings.
 19. The method of claim 18,wherein the strip of material further comprises an intermediate regiondisposed between the first porous ingrowth material and the secondporous ingrowth material.
 20. The method of claim 18, wherein each ofthe implant blanks has a similar shape.